The lesson here is that we all have something in our background that can be misconstrued or might be made downright embarrassing. And it will come out when running for high office.

Warren was reportedly relying on her parents' word that she was part Native American. Relying on someone's word about an issue that can be as sensitive as claiming to be a member of a tribe may be good enough for an Ivy League faculty directory (though maybe not so much there even), but it simply won't do in the world of big-time politics.

Many employers conduct background checks that look mostly at criminal history, but even then, many employers don't care about drunk-driving incidents that took place 25 years ago. Voters are otherwise: there's an argument to be had that the last-minute 2000 election revelation of George W Bush's 1976 drunk-driving arrest cost Bush evangelical votes and nearly the election.

Likewise, most employers merely read a resume or curriculum vitae and rely on an applicant's accuracy and honesty without checking further. We know that neither Harvard nor Pennsylvania investigated the issue of Warren's ancestry.

Political campaign operatives, however, such as the infamous Roger Stone, are paid to dig up the dirt that you would rather keep hidden – or didn't even know about. As the 2000 Bush incident demonstrates, "new" information can often be turned out not only about a new first-time candidate, but even about a long-time candidate running for higher office.

The issue here is that many lower-end campaigns don't have the resources for such muck-raking; and the press doesn't care to spend resources on what may prove fruitless researches of the past, either. Other times, investigators just look in the wrong places.

Virginia Governor Bob McDonnell's college thesis, which many construed as sexist, became a focal point for a short time in his 2009 gubernatorial run, but did you know he had actually faced a much tighter race for attorney general just four years earlier? The story didn't hit the wires at all during that campaign; yet, now it dogs any vice-presidential aspirations he may have had.

Other candidates know they have faults, but they have to hope that any unfavorable story will be old news and voters will forgive them. Somehow, Newt Gingrich climbed to the top of the Republican primary polls not once, but twice. Republican voters certainly knew about the rocky Newt Gingrich speakership and its scandals, but they seemingly forgot how it had cost them seats in the 1998 House elections. Then the Romney Super Pac ads reminded them, and it was all over Gingrich.

Voters don't necessarily agree that the past is, simply, past – with what, I believe, is good reason. Anyone can say anything about what they will do in the future. But voters are smart, too: they can see beyond what is beltway gossip and judge what is a real scandal. Bill Clinton's voter approval skyrocketed after the Monica Lewinsky affair, even if they thought he was a jerk. Bush won re-election with the help of evangelicals in 2004. Meanwhile, voters did care about Gingrich's past because it demonstrated an inability to lead. We'll see what happens with McDonnell when he faces a more competitive race.

So, what does this all mean for Liz Warren? Initial polls taken after the furor showed her maintaining her poll position in a dead-even race with Republican Scott Brown. That's not unusual. Republican voters stayed by Herman Cain after the initial allegations of sexual harassment, only to abandon him as the media story charges mounted.

What matters for Warren is what happens to her numbers over the next couple of weeks as the saga runs its course. If she is still in a tie with Brown by the beginning of June, Massachusetts voters are probably never going to care about Warren's non-Native American background. If, however, the daily drip-drip becomes a narrative that makes voters question her credibility, then she's in a fight.

The takeaway for all candidates that if you know you've done something you shouldn't have, expect it to come out. And even if it's something you don't know, as Warren claims, or don't "remember" (as in Mitt Romney and his high-school "hijinks"), you should still expect some unwelcome something to come out.

You can run from your past, but you can't hide.

• This article was amended to avoid implying that Elizabeth Warren may have made reference to possible Native American ancestry in university job applications; there is no evidence that she did so. The correction was made at 3.45pm EST on 21 May 2012